WELLFLEET — Health and Conservation Agent Hillary Greenberg-Lemos issued a warning on Wednesday that the Eastern equine encephalitis (EEE) virus had been detected in Wellfleet. The rare but deadly disease is contracted from the bite of an infected mosquito.
Greenberg-Lemos said that residents should try to avoid being bitten. “I don’t think they should be super concerned, but it is here so there is a general risk,” she said. “We ask that people do take precautions.”
To monitor the virus’s prevalence and geographic distribution, the Cape Cod Mosquito Control Project regularly tests mosquitoes. “The monitoring is continuous at different places all around Wellfleet,” Greenberg-Lemos said. “We only have one location that picked up a positive sample.”
The Mass. Bureau of Infectious Disease and Laboratory Sciences (BIDLS) released a risk map on Tuesday that depicts EEE risk levels for every town in the state. The towns on the Outer Cape were shown as low risk, except Truro, which was at moderate risk. On Thursday, Wellfleet’s risk level was raised from low to moderate.
“My guess is, once they find a positive sample, it goes from low to moderate,” Greenberg-Lemos said Thursday. “Our results just came in yesterday afternoon.”
According to the BIDLS’s list of positive mosquito samples, two mosquitoes tested positive for EEE virus in Truro, one on Aug. 1 and another on Aug. 22. One mosquito tested positive in Wellfleet on Aug. 29. Neither Provincetown nor Eastham had any mosquitoes that tested positive.
Greenberg-Lemos’s warning urges residents to avoid mosquito bites by remaining indoors during peak mosquito hours (dusk to dawn), reducing skin exposure by wearing socks, long-sleeved shirts and long pants, and applying insect repellent when outdoors.
As mosquitoes lay eggs in standing water, the warning also recommends draining any standing water around the house. Repairing or installing screens is also a good idea.
Horses can also contract EEE. The warning suggests that horses be housed in stalls overnight and water troughs be regularly flushed.
Mosquitoes carrying the EEE virus are typically found along the Atlantic and Gulf coasts from late spring through early fall. After September, as mosquito populations decrease with the temperature, the risk will also go down.
The EEE virus is transmitted to humans by infected mosquitoes. But only 4 to 5 percent of EEE virus infections in humans result in symptoms, which include chills, fever, malaise, and joint and muscle pain. Symptoms appear from 4 to 10 days after infection.
According to the Centers for Disease Control website, developing EEE after infection with the virus is very rare — in the U.S., an average of seven cases are reported each year — but deadly. Approximately one-third of people with EEE die, typically 2 to 10 days after the first symptoms appear. Survivors may sustain severe brain damage and associated impairments, including personality disorders, paralysis, and seizures. Older adults and children under 15 with EEE are particularly at risk.
There is currently no vaccine against EEE infection or cure for EEE.